Siemens Ltd. Vietnam and Vietnam Motors Industry Corporation (Vinamotor) headquartered in Hanoi have entered a cooperation agreement to apply Siemens Elfa hybrid drive technology for city buses in Vietnam. A prototype of the Elfa will be built in 2012. Siemens will supply all necessary components and provide technical support, while Vinamotor will prepare the platform and manufacture remaining parts of the bus for operational readiness. With the Siemens hybrid drive technology, city buses can significantly reduce fuel consumption and save operating cost by up to 50 percent. In Vietnam, the public transport system is facing challenges that go along with the growing transportation needs of urban residents. Within the framework of a cooperation agreement between Siemens Vietnam and Vinamotor, city buses in Vietnam will be equipped with Siemens Elfa system, a diesel-electric hybrid drive concept. It combines mobile energy generators, such as diesel generator sets and high performance energy storage devices. These allow the energy that is released when braking to be harnessed and stored. With conventional city buses, breaking energy is simply converted into heat and lost. For Elfa hybrid technology, the breaking energy is converted into electrical energy by the generative operation of the traction motor and is fed into an energy storage device – in high-performance capacitors or batteries. The stored energy is reused when starting and accelerating. Depending on the storage capacity of the system, the bus can also be driven purely electrically, i.e., emission-free, especially in inner city areas and at bus stops. As such, operating companies can profit from significant fuel cost savings of up to 50 percent and reduce impact on the environment through lower exhaust emission. In addition, passengers can benefit from noticeably quieter operation due to a smoother start and acceleration of these buses.